With reserves of fossil fuel decrease, environmental pollution and energy shortage have been predominant and highly concerned. In order to solve the above problem, China is now striving to develop new energies such as wind power, and wind power generation has stepped into steady development after rapid growth for many years. Although the problem of wind power grid connection has been eased to a certain extent in recent years, after wind power gets access into the system, it will still cause a series of problems, which limits the further development of the wind power. Among the problems, small disturbance stability problem generated after grid connection of wind power is especially acute. At present, the mainstream model of wind turbines in China is double-fed induction generator. After getting access to the system, the generators will lead to weak damping mode, reduce system small disturbance stability margin and increase the risks for the system to operate normally. Therefore, it is very urgent to research how to improve small disturbance stability after double-fed unit gets access to the system.
Traditional methods for improving small disturbance stability after wind turbines get access to the system mainly include adopting some algorithm to optimize overall parameters or adding PSS device. The former method is of a large workload with modest effect and it cannot effectively control certain several dominant modes; the latter one is of obvious effect, but the parameter adjustment is complex and the investment cost will also rise. For the method of using sensitivity analysis to optimize system parameters mentioned in the present invention, sensitivity analysis can be made on the weak damping mode and relevant parameters can be comprehensively selected through analyzing change of eigenvalues according to analysis results of system characteristic matrixes. In this way, for a series of unstable modes or weak damping modes generated for selecting parameters unreasonably, relevant modal damping can be improved without adding other devices. Besides, this method also can greatly decrease the workload generated by unnecessary try, so that it is instructive for how to set system parameters.